diff --git a/nimbus/config.nim b/nimbus/config.nim
index ce2ab3fe2..725ea52c2 100644
--- a/nimbus/config.nim
+++ b/nimbus/config.nim
@@ -340,7 +340,7 @@ proc processEthArguments(key, value: string): ConfigStatus =
       config.keyFile = value
     else:
       result = ErrorIncorrectOption
-  of "dataDir":
+  of "datadir":
     config.dataDir = value
   of "prune":
     result = processPruneList(value, config.prune)